In the prior art, the diffuser is often secured inside an outer casing of the combustion chamber by a thin wall or web of frustoconical shape which extends from an outer longitudinal wall of the diffuser towards the combustion chamber, and which is welded at its radially outer end to the outer casing of the combustion chamber.
The drawback of that prior art is that the diffuser, which has a lifetime that is considerably shorter than that of the combustion chamber casing, is not separable from the casing.
It is therefore desirable to secure the diffuser in removable manner to the outer casing of the combustion chamber. In order to make it easier to remove the diffuser, a better technique would be to secure it by means of an outer annular flange inserted between the annular flanges for coupling together the outer casings of the compressor and of the combustion chamber.
For that purpose, it would be necessary for a diffuser-fastening frustoconical wall or web to extend from the diffuser towards the compressor. Nevertheless, that is not possible because of constraints associated with taking air from the compressor, whereby an annular space formed around the stator of the compressor extends downstream to the vicinity of the upstream portion of the diffuser and is defined by a transverse wall that is secured to the outer casing of the compressor and that constitutes an obstacle in this location against receiving a diffuser-fastening frustoconical wall or web extending from the diffuser towards the compressor.
That problem might be solved by means of structural arms connected to the outer longitudinal wall of the diffuser downstream from the stator blades, but that would require the diffuser to be made in two parts, which would complicate manufacture and increase its cost.